Yeah, I use RXP regularly in the pickup ('69 F100) and the Zook. It burns out the carbon deposits in the combustion chamber- they say it changes the IR flame front characteristics and I can definitely tell a difference if the things have been running rough prior to using it vs. perhaps even a half -hour of operation after adding it to the gas tank. I've seen it clean up a coked-up EGR passage before, too, in the Suburban. If you have to pass an emissions sniffer test to get an inspection sticker, adding a bottle on each of the two tankfulls prior to sniff test will clean it right up.
It does seem to work a lot better on engines with more miles, but even on the wife's new truck it does give a
'seat of the pants' increase that i can feel.
To me, it's just about the best 7 bucks I spend for an additive, especially since we have to run a 10% ethanol blend around here. The B12 is great for dirty fuel systems/carbs/injectors because it degums all the orfices, whereas RXP is active in the combustion process.
Regards,
Rabbit.
